Patentable/Patents/US-7442631
US-7442631

Doping method and method of manufacturing field effect transistor

PublishedOctober 28, 2008
Assigneenot available in USPTO data we have
Inventorsnot available in USPTO data we have
Technical Abstract

A doping method comprising the steps of; obtaining a proportion X of ions of a compound including a donor or an acceptor impurity in total ions from mass spectrum by using a first source gas of a first concentration; analyzing a peak concentration Y of the compound in a first processing object which is doped by using a second source gas of a second concentration equal to or lower than the first concentration, referring to a dose amount of total ions as D0 and setting an acceleration voltage at a value, obtaining a dose amount D1 of total ions from a expression, Y=(D1/D0)(aX+b), and doping a second processing object with the donor or the acceptor impurity by a ion doping apparatus using a third source gas, wherein a dose amount of total ions is set at D1, and an acceleration voltage is set at the value.

Patent Claims
20 claims

Legal claims defining the scope of protection, as filed with the USPTO.

1

1. A doping method comprising the steps of: obtaining a proportion X (0<X<1) of ions of a compound including a donor impurity or an acceptor impurity in total ions from mass spectrum by generating plasma using a first source gas in which the compound including the donor impurity or the acceptor impurity is diluted with a diluent gas made of hydrogen or a rare gas to a first concentration of 5% to 40% in an ion doping apparatus, analyzing a peak concentration Y of the compound including the donor impurity or the acceptor impurity in a first processing object which is doped with the ions of the compound including the donor impurity or the acceptor impurity by the ion doping apparatus using a second source gas in which the compound including the donor impurity or the acceptor impurity is diluted with the diluent gas to a second concentration lower than the first concentration, referring to a dose amount of total ions as D 0 and setting an acceleration voltage at a value, obtaining a dose amount D 1 of total ions from a relational expression, Y=(D 1 /D 0 )(aX +b), wherein a and b are assumed to be real numbers, and doping a second processing object with the donor impurity or the acceptor impurity by the ion doping apparatus using a third source gas, wherein a dose amount of total ions is set at D 1 , and an acceleration voltage is set at the value.

2

2. The doping method according to claim 1 , wherein the peak concentration Y is analyzed by secondary ion mass spectrum (SIMS) analysis.

3

3. The doping method according to claim 1 , wherein a plasma treatment is performed to a dummy substrate using plasma of the diluent gas for a predetermined period while the first source gas diluted to the first concentration is changed to the second source gas diluted to the second concentration.

4

4. The doping method according to claim 1 , wherein the compound of the acceptor impurity is B 2 H 6 (diborane), and the ions of the compound including the acceptor impurity is B 2 H y 30 ions (y is a positive integer).

5

5. The doping method according to claim 1 , wherein the dose amount D 1 is obtained by an electronic calculator.

6

6. A doping method comprising the steps of: obtaining a proportion X of ions of a compound including a donor impurity or an acceptor impurity in total ions from mass spectrum by generating plasma using a first source gas in which the compound including the donor impurity or the acceptor impurity is diluted with a diluent gas made of hydrogen or a rare gas to a first concentration of 5% to 40% in an ion doping apparatus; and analyzing a peak concentration Y of the compound including the donor impurity or the acceptor impurity in a first processing object which is doped with ions of the compound including the donor impurity or the acceptor impurity by the ion doping apparatus using a second source gas in which the compound including the donor impurity or the acceptor impurity is diluted with the diluent gas to a second concentration lower than the first concentration, referring a dose amount of total ions to be D 0 and setting an acceleration voltage at a value, obtaining a dose amount D 1 of total ions from a first relational expression, Y=(D 1 /D 0 )(aX +b), and from a second relational expression, V th =cY 1/2 +d, wherein a, b, c and d are assumed to be real numbers, and doping a second processing object with the donor impurity or the acceptor impurity by the ion doping apparatus using a third source gas, wherein a dose amount of total ions is set at D 1 , and an acceleration voltage is set at the value, and wherein Vth is a threshold voltage of a field effect transistor manufactured by using the second processing object which is doped with the donor impurity or the acceptor impurity.

7

7. The doping method according to claim 6 , wherein the peak concentration Y is analyzed by secondary ion mass spectrum (SIMS) analysis.

8

8. The doping method according to claim 6 , wherein a plasma treatment is performed to a dummy substrate using plasma of the diluent gas for a predetermined period while the first source gas diluted to the first concentration is changed to the second source gas diluted to the second concentration.

9

9. The doping method according to claim 6 , wherein the compound of the acceptor impurity is B 2 H 6 (diborane), and the ions of the compound including the acceptor impurity is B 2 H y + ions (y is a positive integer).

10

10. The doping method according to claim 6 , wherein the dose amount D 1 is obtained by an electronic calculator.

11

11. A manufacturing method of a field effect transistor comprising the steps of: obtaining a proportion X (0<X<1) of ions of a compound including a donor impurity or an acceptor impurity in total ions from mass spectrum by generating plasma using a first source gas in which the compound including the donor impurity or the acceptor impurity is diluted with a diluent gas made of hydrogen or a rare gas to a first concentration of 5% to 40% in an ion doping apparatus, analyzing a peak concentration Y of the compound including the donor impurity or the acceptor impurity in a first processing object which is doped with the ions of the compound including the donor impurity or the acceptor impurity by the ion doping apparatus using a second source gas in which the compound including the donor impurity or the acceptor impurity is diluted with the diluent gas to a second concentration lower than the first concentration, referring to a dose amount of total ions as D 0 and setting an acceleration voltage at a value, obtaining a dose amount D 1 of total ions from a relational expression, Y=(D 1 /D 0 )(aX+b), wherein a and b are assumed to be real numbers, and doping a second processing object with the donor impurity or the acceptor impurity by the ion doping apparatus using a third source gas, wherein a dose amount of total ions is set at D 1 , and an acceleration voltage is set at the value.

12

12. The manufacturing method of the field effect transistor according to claim 11 , wherein the peak concentration Y is analyzed by secondary ion mass spectrum (SIMS) analysis.

13

13. The manufacturing method of the field effect transistor according to claim 11 , wherein a plasma treatment is performed to a dummy substrate using plasma of the diluent gas for a predetermined period while the first source gas diluted to the first concentration is changed to the second source gas diluted to the second concentration.

14

14. The manufacturing method of the field effect transistor according to claim 11 , wherein the compound of the acceptor impurity is B 2 H 6 (diborane), and the ions of the compound including the acceptor impurity is B 2 H y + ions (y is a positive integer).

15

15. The manufacturing method of the field effect transistor according to claim 11 , wherein the dose amount D 1 is obtained by an electronic calculator.

16

16. A manufacturing method of a field effect transistor comprising the steps of: obtaining a proportion X of ions of a compound including a donor impurity or an acceptor impurity in total ions from mass spectrum by generating plasma using a first source gas in which the compound including the donor impurity or the acceptor impurity is diluted with a diluent gas made of hydrogen or a rare gas to a first concentration of 5% to 40% in an ion doping apparatus; and analyzing a peak concentration Y of the compound including the donor impurity or the acceptor impurity in a first processing object which is doped with ions of the compound including the donor impurity or the acceptor impurity by the ion doping apparatus using a second source gas in which the compound including the donor impurity or the acceptor impurity is diluted with the diluent gas to a second concentration lower than the first concentration, referring a dose amount of total ions to be D 0 and setting an acceleration voltage at a value, obtaining a dose amount D 1 of total ions from a first relational expression, Y=(D 1 /D 0 )(aX+b), and from a second relational expression, V th =cY 1/2 +d, wherein a, b, c and d are assumed to be real numbers, and doping a second processing object with the donor impurity or the acceptor impurity by the ion doping apparatus using a third source gas, wherein a dose amount of total ions is set at D 1 , and an acceleration voltage is set at the value, and wherein Vth is a threshold voltage of the field effect transistor manufactured by using the second processing object which is doped with the donor impurity or the acceptor impurity.

17

17. The manufacturing method of the field effect transistor according to claim 16 , wherein the peak concentration Y is analyzed by secondary ion mass spectrum (SIMS) analysis.

18

18. The manufacturing method of the field effect transistor according to claim 16 , wherein a plasma treatment is performed to a dummy substrate using plasma of the diluent gas for a predetermined period while the first source gas diluted to the first concentration is changed to the second source gas diluted to the second concentration.

19

19. The manufacturing method of the field effect transistor according to claim 16 , wherein the compound of the acceptor impurity is B 2 H 6 (diborane), and the ions of the compound including the acceptor impurity is B 2 H y + ions (y is a positive integer).

20

20. The manufacturing method of the field effect transistor according to claim 12 , wherein the dose amount D 1 is obtained by an electronic calculator.

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Patent Metadata

Filing Date

February 3, 2006

Publication Date

October 28, 2008

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